prow cluster: create loop devices in advance

[pohly]

This is a workaround for dynamic device creation not working inside
KinD nodes.

Fixes: kubernetes-sigs/kind#1248 kubernetes/kubernetes#87953

[pohly]

I have verified that:

• Deploying this daemonset on a normal cluster populates /dev as intended.
• That the nodes in a KinD cluster with fully populated /dev also then have the same /dev/loopX entries.

I have not verified that this really works in the Kubernetes prow. I'm not even sure whether the daemonset will be deployed automatically?

I modeled this after https://github.com/kubernetes/test-infra/blob/b2d632960440e47f671dd3b997709aa299911456/prow/cluster/tune-sysctls_daemonset.yaml.

/cc @BenTheElder

[BenTheElder]

it can be deployed if added to the bazel rules for deploying prow, see 75edf5a#diff-f677234fb7028152fac5bac409d77567

[BenTheElder]

/lgtm
/approve
will do deployment in a follow up
this hack is sorta gross, but also only something we should need, the average KIND user is probably not using block devices ... I hope!

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: BenTheElder, pohly

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Needs approval from an approver in each of these files:

• prow/cluster/OWNERS [BenTheElder]

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment